Nowadays, geodetic surveying methods, which use global navigation satellite systems can reach a sub-centimeter positioning accuracy. This accuracy is in particular achieved by using techniques, such as differential measurement methods or multi-channel receivers. In differential measurement methods, measurements with two devices are conducted simultaneously. Multi-channel receivers can receive signals of multiple satellites.
A further advantage residing in using global navigation satellite systems for geodetic surveying measurements is that no line of sight connection between individual surveying instruments is necessary. Moreover, weather and day time conditions are less critical for such measurements compared to terrestrial measurements of a similar accuracy.
However, reception of signals of a global navigation satellite system can be poor in the intermediate vicinity of obstacles. Examples for such obstacles can be foliage or brickwork structures.
It is therefore advantageous to apply a combination of different surveying techniques, such as a combination of terrestrial surveying techniques with a surveying system using a global navigation satellite system.